This invention relates generally to a method for continuously slurrying adhesive solids in an aqueous medium, cooking and cutting the slurry with an alkali cutting agent so as to disperse the solids and thereby create a homogeneous water soluble adhesive for use as a coating binder.
In the past it has always been advantageous to purchase coating ingredients in dry form because of considerable savings on freight and energy. Previously, however the manufacturer of the coating adhesive would prepare the formulation onsight in a batch wise system. The dry powder was added to water with agitation and heated in a steam jacketed vessel or by sparging steam directly into the slurry. There was a wetting-in period of approximately 5 minutes. At the end of the wet-in period, a suitable alkali was added to the slurry and the temperature of the mixture was adjusted to between 140.degree. and 160.degree. F. while the slurry was mixed for approximately 30 minutes. There were several drawbacks to that method. Clearly, it was cumbersome and time consuming, but more importantly the method permitted manufacture of an adhesive which was limited to no more than 14 to 18% solids. A large reaction vessel was essential, and an unduly long heating period was necessary, accurate and reproduceable mixtures were infrequent and an excessive energy demand was placed upon the batch system in which the reaction took place.
In accordance with this invention, it is possible to eliminate the manual batch wise operations, to reduce the necessary energy, and to significantly increase the rate of output. It is also possible to accurately reproduce the mixtures on a continuous basis.